Abstract The Clinical Core serves to support the two research projects of the U19 research program. The Clinical Core will provide the research projects with appropriate human clinical specimens and data from different studies to better understand adaptive and innate immunity to vaccination for Streptococcus pneumoniae and varicella zoster virus. The specific aims of the Clinical Core are: Specific aim 1) To provide clinical study expertise and capacity to ensure the success of the U19 scientific agenda. The support activities to be provided include: study design; clinical protocol and informed consent form preparation; obtaining required regulatory approvals; designing case report forms and the clinical database; outreach and education with communities in which recruiting will occur; recruitment, screening, and enrollment; clinical study conduct according to Good Clinical Practice (GCP) standards; establish a system of records, including source data and essential documents; subject safety monitoring; clinical specimen collection, processing, tracking, storage, and shipping; preparation of progress reports, final report, presentations, and publications. Specific aim 2) To perform clinical studies with varicella vaccine, zoster vaccine, and pneumococcal vaccines in different populations (children, adults, elderly and immunocompromised) that will provide the clinical specimens and data necessary to accomplish the scientific aims of the related research projects. Specific aim 3) To perform assays for endpoint immune responses that will provide read out for varicella zoster virus (VZV) serology and blood count assays.